Sulphite Rinses
for Schiff’s Reagent Reactions
Following the application of Schiff’s reagent, the excess must be removed somehow. In the past, it was thought that rinsing with water could cause recoloration of the Schiff’s reagent, which would then stain the tissue giving the appearance of positive staining. Sulphite rinses were developed to inhibit recoloration, by rinsing off Schiff’s reagent with the solvent used to make it.
It is now known this is not necessary and, provided the sections do not stay in recolored Schiff reagent for any length of time, nonspecific staining does not take place. It is common practice now to simply wash in running tap water for about 20 minutes.
Materials
Solution A
| Material | Amount | |
|---|---|---|
| Sodium metabisulphite | 5 | g |
| Distilled water | 100 | mL |
Note: Potassium metabisulphite may also be used in Solution A.
Solution B
| Material | Amount | |
|---|---|---|
| Hydrochloric acid, conc | 1 | mL |
| Distilled water | 1 | L |
Working Solution
| Material | Amount | |
|---|---|---|
| Solution A | 1 | volume |
| Solution B | 9 | volumes |
Procedure
- Place sections directly from Schiff’s reagent into three changes of the working solution for about 2 minutes each.
- Wash in running tap water for ten minutes.
- Continue on with the stain.
- Discard the solutions if they become distinctly red.
Safety Note
Prior to handling any chemical, consult the Safety Data Sheet (SDS) for proper handling and safety precautions.
References
- Lillie, R.D., (1954)
Histopathologic technique and practical histochemistry Ed.2
Blakiston, New York, USA
